Method and apparatus for handling emergency services in a wireless network

ABSTRACT

Methods and systems for handling emergency services in a wireless network. A method disclosed herein includes enabling at least one User Equipment (UE) supporting only Closed Access Group (CAG) cell/non-public network (NPN) to camp onto at least one non-CAG cell/public network cell to access the emergency services. The method further includes enabling the at least one UE to switch behavior of a timer from a periodic registration timer with a “Strictly Periodic Registration Timer Indication” to a normal periodic registration timer/pre-release 16 behavior for performing the emergency services.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119(a) to Indian Provisional Application No. 201941024005 filed on Jun.17, 2019, and Indian complete Application No. 201941024005 filed on Jun.8, 2020 in the Indian Patent Office, the disclosures of which are hereinincorporated by reference in their entirety.

BACKGROUND 1. Field

The present disclosure relates to the field of wireless networks andmore particularly to handling emergency services in a wireless network.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4th generation (4G) communication systems, efforts havebeen made to develop an improved 5th generation (5G) or pre-5Gcommunication system. The 5G or pre-5G communication system is alsocalled a ‘beyond 4G network’ or a ‘post long term evolution (LTE)system’. The 5G communication system is considered to be implemented inhigher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplishhigher data rates. To decrease propagation loss of the radio waves andincrease the transmission distance, the beamforming, massivemultiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO),array antenna, an analog beamforming, and large scale antenna techniquesare discussed with respect to 5G communication systems. In addition, in5G communication systems, development for system network improvement isunder way based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like.

In the 5G system, hybrid frequency shift keying (FSK) and Feher'squadrature amplitude modulation (FQAM) and sliding window superpositioncoding (SWSC) as an advanced coding modulation (ACM), and filter bankmulti carrier (FBMC), non-orthogonal multiple access (NOMA), and sparsecode multiple access (SCMA) as an advanced access technology have beendeveloped.

The Internet, which is a human-centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofeverything (IoE), which is a combination of the IoT technology and thebig data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing information technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, MTC, and M2M communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RAN as theabove-described big data processing technology may also be considered tobe as an example of convergence between the 5G technology and the IoTtechnology.

As described above, various services can be provided according to thedevelopment of a wireless communication system, and thus a method foreasily providing such services is required.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below.

Accordingly, an aspect of the disclosure is to provide methods andsystems for handling emergency services in a wireless network. A methoddisclosed herein includes initiating at least one emergency servicewhile operating in a Closed Access Group (CAG) only mode. The methodfurther includes selecting a non-CAG cell from a plurality of non-CAGcells in a Public Land Mobile Network (PLMN). The method furtherincludes performing the initiated at least one emergency service bycamping onto the selected non-CAG cell.

In an embodiment of the disclosure, wherein the wireless networkincludes at least one Non-Public Network (NPN) connected to the PLMN,wherein the at least one NPN is at least one CAG cell.

In an embodiment of the disclosure, wherein in the CAG only mode, the UEconnects only to the at least one CAG cell to access the PLMN, whereinthe at least one CAG cell provides at least one private service to theUE.

In an embodiment of the disclosure, wherein each of the plurality ofnon-CAG cells is a public Radio Access Network (RAN) connected to atleast one Core Network (CN) of at least one Radio Access Technology(RAT) present in the PLMN.

In an embodiment of the disclosure, wherein each non-CAG cell supportsthe at least one CAG cell and provides at least one normal communicationservice and the at least one emergency service to the UE.

In an embodiment of the disclosure, wherein selecting, by the UE, thenon-CAG cell includes: disabling the CAG only mode; determining theplurality of non-CAG cells available in a location of the UE based on atleast one signal broadcasted by the plurality of non-CAG cells; andselecting the non-CAG cell from the plurality of non-CAG cells based onat least one factor associated with the at least one signal broadcastedby the plurality of non-CAG cells, wherein the at least one factorincludes at least one of signal strength, and reference signal receivepower. In an embodiment of the disclosure, wherein the UE selects thenon-CAG cell for the initiated at least one emergency service when theUE does not determine the at least one CAG cell in the location, or whenthe at least one CAG cell connected to the UE does not support theinitiated at least one emergency service.

In an embodiment of the disclosure, wherein performing, by the UE, theinitiated at least one emergency service includes: camping on to theselected non-CAG cell and establishing a Radio Resource Control (RRC)connection with the selected non-CAG cell, wherein the non-CAG cellconnects the UE to the associated at least one CN; establishing anemergency Protocol Data Unit (PDU) session with an external data networkthrough the at least one CN by performing an emergency attach procedurewith the at least one CN through the selected non-CAG cell; andperforming the initiated at least one emergency service over theestablished emergency PDU session.

In an embodiment of the disclosure, the method further comprises:entering, by the UE, into an idle mode on completing the initiatedemergency service; remaining, by the UE, in the idle mode for apre-defined period of time; and enabling, by the UE, the CAG only modeon an expiry of the pre-defined period of time.

In an embodiment of the disclosure, wherein the UE enables the CAG onlymode by performing a registration update procedure with the at least oneCN of the PLMN.

In an embodiment of the disclosure, the method further comprising:establishing, by the UE, the emergency PDU session with the at least oneCAG cell for performing the initiated at least one emergency service,when the UE is camped on the at least one CAG cell during the CAG onlymode; determining, by the UE, a connection loss with the camped at leastone CAG cell, while performing the at least one emergency servicethrough the camped at least one CAG cell; and selecting, by the UE, thenon-CAG cell for completing the at least one emergency service ondetermining the connection loss with the camped at least one CAG cell.

Accordingly, an aspect of the disclosure is to provide a User Equipment(UE) for managing emergency services in a wireless network, wherein theUE includes a memory and a controller. The controller is configured toinitiate at least one emergency service, while the UE is operating in aClosed Access Group (CAG) only mode. The controller is furtherconfigured to select a non-CAG cell from a plurality of non-CAG cells ina Public Land Mobile Network (PLMN). The controller is furtherconfigured to perform the initiated at least one emergency service byenabling the UE to camp onto the selected non-CAG cell.

In an embodiment of the disclosure, wherein the wireless networkincludes at least one Non-Public Network (NPN) connected to the PLMN,wherein the at least one NPN is at least one CAG cell.

In an embodiment of the disclosure, wherein in the CAG only mode, the UEconnects only to the at least one CAG cell to access the PLMN, whereinthe at least one CAG cell provides at least one private service to theUE.

In an embodiment of the disclosure, wherein each of the plurality ofnon-CAG cells is a public Radio Access Network (RAN) connected to atleast one Core Network (CN) of at least one Radio Access Technology(RAT) present in the PLMN.

In an embodiment of the disclosure, wherein each non-CAG cell supportsthe at least one CAG cell and provides at least one normal communicationservice and the at least one emergency service to the UE.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to: disable the CAG only mode; determine the plurality ofnon-CAG cells available in a location of the UE based on at least onesignal broadcasted by the plurality of non-CAG cells; and select thenon-CAG cell from the plurality of non-CAG cells based on at least onefactor associated with the at least one signal broadcasted by theplurality of non-CAG cells, wherein the at least one factor includes atleast one of signal strength, and reference signal receive power.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to: select the non-CAG cell for the initiated at least oneemergency service when the UE does not determine the at least one CAGcell in the location, or when the at least one CAG cell connected to theUE does not support the initiated at least one emergency service.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to: enable the UE to camp on to the selected non-CAG cell andto establish a Radio Resource Control (RRC) connection with the selectednon-CAG cell, wherein the non-CAG cell connects the UE to the associatedat least one CN; enable the UE to establish an emergency Protocol DataUnit (PDU) session with an external data network through the at leastone CN by performing an emergency attach procedure with the at least oneCN through the selected non-CAG cell; and perform the initiated at leastone emergency service over the established emergency PDU session.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to: enable the UE to enter into an idle mode on completingthe initiated emergency service; enable the UE to remain in the idlemode for a pre-defined period of time; and enable the CAG only mode onan expiry of the pre-defined period of time.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to enable the CAG only mode by enabling the UE to perform aregistration update procedure with the at least one CN of the PLMN.

In an embodiment of the disclosure, wherein the controller is furtherconfigured to: enable the UE to establish the emergency PDU session withthe at least one CAG cell for performing the initiated at least oneemergency service, when the UE is camped on the at least one CAG cellduring the CAG only mode; determine a connection loss with the camped atleast one CAG cell, while performing the at least one emergency servicethrough the camped at least one CAG cell; and select the non-CAG cellfor completing the at least one emergency service on determining theconnection loss with the camped at least one CAG cell.

Accordingly, an aspect of the disclosure is to provide a wirelessnetwork system comprising: a Public Land Mobile Network (PLMN) includinga plurality of non-Closed Access Group (CAG) cells and at least one CoreNetwork (CN) of at least one Radio Access Technology (RAT); at least oneCAG cell coupled to the PLMN, wherein the at least one CAG cell is atleast one Non-Public Network (NPN); and a plurality of User Equipments(UEs) supporting the at least one CAG cell and the PLMN, wherein a UE ofthe plurality of UEs is configured to: initiate at least one emergencyservice while operating in a CAG only mode; select the non-CAG cell fromthe plurality of non-CAG cells in the PLMN; and perform the initiated atleast one emergency service by camping onto the selected non-CAG cell.

In an embodiment of the disclosure, wherein the UE connects only to theat least one CAG cell to access the PLMN in the CAG only mode.

In an embodiment of the disclosure, wherein each non-CAG cell supportsthe at least one CAG cell and provides at least one normal communicationservice and the at least one emergency service to the UE.

In an embodiment of the disclosure, wherein the UE is further configuredto: disable the CAG only mode; determine the plurality of non-CAG cellsavailable in a location of the UE based on at least one signalbroadcasted by the plurality of non-CAG cells; and select the non-CAGcell from the plurality of non-CAG cells based on at least one factorassociated with the at least one signal broadcasted by the plurality ofnon-CAG cells, wherein the at least one factor includes at least one ofsignal strength, and reference signal receive power.

In an embodiment of the disclosure, wherein the UE is further configuredto: camp on to the selected non-CAG cell and to establish a RadioResource Control (RRC) connection with the selected non-CAG cell,wherein the non-CAG cell connects the UE to the associated at least oneCN; establish an emergency Protocol Data Unit (PDU) session with anexternal data network through the at least one CN by performing anemergency attach procedure with the at least one CN through the selectednon-CAG cell; and perform the initiated at least one emergency serviceover the established emergency PDU session.

In an embodiment of the disclosure, wherein the at least one CN isconfigured to perform a handover of the UE from the at least one CAGcell to the non-CAG cell for completing the at least one emergencyservice, when the UE loses connection with the at least one CAG cellwhile performing the at least one emergency service through the at leastone CAG cell.

According to an embodiment of the disclosure, an aspect of thedisclosure is to provide methods and systems for handling emergencyservices in a wireless network. The method comprising: receiving, by aUser Equipment (UE), a periodic registration timer value with a“Strictly Periodic Registration Timer Indication” indication from a CoreNetwork (CN); operating, by the UE, a timer in a strictly periodicregistration mode in response to the received periodic registrationtimer value with the “Strictly Periodic Registration Timer Indication”indication; initiating, by the UE, at least one emergency service whilethe timer is operating; switching, by the UE, behavior of the timer fromthe strictly periodic registration mode to a normal periodicregistration mode on initiating the at least one emergency service; andperforming, by the UE, the initiated at least one emergency service onthe behavior of the timer being switched.

In an embodiment of the disclosure, wherein in the strictly periodicregistration mode, the UE continues to operate the timer with theperiodic registration timer value, when the UE moves from an idle modeto a connected mode, and when the UE moves from the connected mode tothe idle mode.

In an embodiment of the disclosure, wherein in the normal periodicregistration mode, the UE terminates the timer, when the UE moves fromthe idle mode to the connected mode.

In an embodiment of the disclosure, wherein in the normal periodicregistration mode, the UE resets and restarts the timer, when the UEmoves from the connected mode to the idle mode.

In an embodiment of the disclosure, a User Equipment (UE) in a wirelessnetwork comprising: a memory; and a periodic registration controllercoupled to the memory configured to: receive a periodic registrationtimer value with a “Strictly Periodic Registration Timer Indication”indication from a Core Network (CN); operate a timer in a strictlyperiodic registration mode in response to the received periodicregistration timer value with the “Strictly Periodic Registration TimerIndication” indication; initiate at least one emergency service whilethe timer is operating; switch behavior of the timer from the strictlyperiodic registration mode to a normal periodic registration mode oninitiating the at least one emergency service; and perform the initiatedat least one emergency service on the behavior of the timer beingswitched.

In an embodiment of the disclosure, wherein in the strictly periodicregistration mode, the UE continues to operate the timer with theperiodic registration timer value, when the UE moves from an idle modeto a connected mode, and when the UE moves from the connected mode tothe idle mode.

In an embodiment of the disclosure, wherein in the normal periodicregistration mode, the UE terminates the timer, when the UE moves fromthe idle mode to the connected mode.

In an embodiment of the disclosure, wherein in the normal periodicregistration mode, the UE resets and restarts the timer, when the UEmoves from the connected mode to the idle mode.

These and other aspects of the example embodiments herein will be betterappreciated and understood when considered in conjunction with thefollowing description and the accompanying drawings. It should beunderstood, however, that the following descriptions, while indicatingexample embodiments and numerous specific details thereof, are given byway of illustration and not of limitation. Many changes andmodifications may be made within the scope of the example embodimentsherein without departing from the spirit thereof, and the exampleembodiments herein include all such modifications.

Before undertaking the detailed description below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation, the term“or,” is inclusive, meaning and/or, the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like, and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout thispatent document, those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIGS. 1A-1D depict are sequence diagrams depicting conventional methodsof handling emergency services while performing a periodic registrationprocedure using a periodic registration timer and a periodicregistration timer with “Strictly Periodic Registration TimerIndication”;

FIGS. 2A, 2B, and 2C depict a wireless communication system/wirelessnetwork for handling emergency services, wherein the wireless networkincludes at least one non-public network (NPN), and at least one publicnetwork, according to an embodiment of the disclosure;

FIG. 3 depicts the UE configured to perform the emergency services bycamping on a non-CAG cell, according to an embodiment of the disclosure;

FIGS. 4A and 4B depict an example scenario of handling the emergencyscenarios in the wireless network, according to an embodiment of thedisclosure;

FIG. 5 is an example sequence diagram depicting the handling of theemergency service using the non-CAG cells, according to an embodiment ofthe disclosure;

FIG. 6 is an example sequence diagram depicting the handling of theemergency service using the non-CAG cells in the wireless network thatincludes a Standalone-NPN (SNPN), according to an embodiment of thedisclosure;

FIG. 7 is a flow diagram depicting a method for handling the emergencyservices in the wireless network including the NPN and the PLMN,according to an embodiment of the disclosure;

FIGS. 8A and 8B depict another wireless network/wireless communicationsystem for handling the emergency services while performing periodicregistration procedures, according to an embodiment of the disclosure;

FIG. 9A depicts the wireless network handling the emergency services byswitching the behavior of the PTAU timer to the normal periodicregistration timer, wherein the wireless network includes a 5G system(5GS), according to an embodiment of the disclosure;

FIG. 9B depicts a UE configured to handle the emergency services byswitching the behavior of the PTAU timer to the normal periodicregistration timer, according to an embodiment of the disclosure;

FIG. 10 is an example sequence diagram depicting the handling of theemergency service by enabling the PTAU timer supporting the “StrictlyPeriodic Registration Timer Indication” to act as the normal periodicregistration timer, according to an embodiment of the disclosure;

FIG. 11 is a flow diagram depicting a method for handling the emergencyservices by switching the behavior of the timer, according to anembodiment of the disclosure;

FIGS. 12A, 12B, and 12C are flow diagrams depicting handling of at leastone priority service in the wireless network, according to an embodimentof the disclosure;

FIG. 13 schematically illustrates the base station according to anembodiment of the disclosure; and

FIG. 14 schematically illustrates a user equipment (UE) according to anembodiment of the disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

FIGS. 1A through 14, discussed below, and the various embodiments usedto describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

The example embodiments herein and the various features and advantageousdetails thereof are explained more fully with reference to thenon-limiting embodiments that are illustrated in the accompanyingdrawings and detailed in the following description. Descriptions ofwell-known components and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. The description herein isintended merely to facilitate an understanding of ways in which theexample embodiments herein can be practiced and to further enable thoseof skill in the art to practice the example embodiments herein.Accordingly, this disclosure should not be construed as limiting thescope of the example embodiments herein.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

Embodiments herein disclose methods and systems for handling emergencyservices in a wireless network.

Embodiments herein enable at least one User Equipment (UE) supportingonly Closed Access Group (CAG) cell/non-public network (NPN) to connectto at least one non-CAG cell/public cell of at least one public networkfor accessing the emergency services.

Embodiments herein enable the at least one UE to switch behavior of atimer from a periodic registration procedure with a “Strictly PeriodicRegistration Timer Indication” to a periodic registration procedure/16pre-release behavior for accessing the emergency services, whileperforming the periodic registration procedure.

The principal object of the embodiments herein is to disclose methodsand systems for handling emergency services in a wireless network.

Another object of the embodiments herein is to disclose methods andsystems for enabling at least one User Equipment (UE) supporting onlyClosed Access Group (CAG) cell/non-public network (NPN) to access theemergency services by camping onto at least one non-CAG cell/publicnetwork cell.

Another object of the embodiments herein is to disclose methods andsystems for enabling the at least one UE to handle the emergencyservices, while performing a periodic registration procedure with atimer, wherein the timer behaves a periodic registration timer with a“Strictly Periodic Registration Timer Indication”.

Another object of the embodiments herein is to disclose methods andsystems for enabling the at least one UE to switch behavior of the timerfrom the periodic registration timer with the “Strictly PeriodicRegistration Timer Indication” to a normal periodic registrationtimer/pre-release 16 behavior for performing the emergency services.

Referring now to the drawings, and more particularly to FIGS. 1A-1D,2A-2C, 3, 4A-4B, 5-7, 8A-8B, 9A-9B, 10-11, 12A-12C, 13 to 14, wheresimilar reference characters denote corresponding features consistentlythroughout the figures, there are shown example embodiments.

FIGS. 1A-1D depict are sequence diagrams depicting conventional methodsof handling emergency services while performing a periodic registrationprocedure using a periodic registration timer and a periodicregistration timer with “Strictly Periodic Registration TimerIndication”.

According to 3rd Generation Partnership Project (3GPP) TS 24.501 and3GPP TS 23.122, the UE can support only private network/non-publicnetworks (NPN). The NPNs may be deployed by enterprises to meet andoptimize coverage, performance, and security requirements of theirbusiness processes. The NPN may use Closed Access Group (CAG) and/or anon-public network identifier to identify a group of subscribers/UEs,who are permitted to use the one or more NPNs (can be referredhereinafter as CAG cell).

When the UE supports only the NPN/CAG cell, the UE can connect to onlythe CAG cell to access public networks (of any Radio Access Technologies(RAT)) for normal services or emergency services. However, coverage ofthe CAG cell is very limited; therefore the UE, supporting only the CAGcell, can perform the emergency services only in a limited coverage.Further, when the UE initiates an emergency service/call and the atleast one CAG cell is not available or the at least one available CAGcell does not support the emergency services, the UE may not able tocomplete the initiated emergency service. Also, the UE may not able toselect any non-CAG cells of any RATs available at a location forperforming the emergency service, as the UE supports only the CAG cell.Thus, in conventional approaches, the UE supporting only CAG cell/NPNmay not able to perform the emergency services on the non-CAG cells.

According to 3GPP TS 24.501, the UE may perform a periodic registrationprocedure with at least one Core Network (CN) of any RAT to register thelocation information and update the mobile registration with the CN. TheUE may use a periodic registration timer or a periodic registrationtimer with “Strictly Periodic Registration Timer Indication” forperforming the periodic registration procedure.

Consider an example scenario as depicted in FIG. 1A, wherein the UEperforms the periodic registration procedure using the periodicregistration timer. The UE sends a periodic registration request to theCN and receives a periodic registration timer value of 12 minutes (forexample) from the CN. The periodic registration timer value indicatesthe time value at which the UE has to perform the periodic registrationprocedure with the CN. On receiving the periodic registration timervalue, the UE starts executing/operating a periodic tracking area update(PTAU) timer by applying the received periodic registration timer value(for example: 12 mins). In an example, the PTAU timer behaves as theperiodic registration timer.

In an example herein, on starting the PTAU timer, the UE may operate inthe connected mode for 4 minutes. After 4 minutes, the UE may enter intothe idle mode. After 2 minutes, the UE exits from the idle mode andstarts data transmission by entering into the connected mode and entersinto the idle mode on completion of the data transmission. When the UEenters into the idle mode, the UE restarts the PTAU timer. Thus, thePTAU timer starts from a value of 0 again. Further, the UE may start thedata transmission by entering into the connected mode after 3 minutes ofrestarting the PTAU timer. On completion of the data transmission, theUE enters into the idle mode and again restarts the PTAU timer. The UEmay remain in the idle mode till the expiry of the PTAU timer and maystart performing the periodic registration procedure. In an exampleherein, the UE may remain in the idle mode for 12 minutes, as the PTAUtimer expires on reaching the value of 12 minutes and may startperforming the periodic registration procedure after 12 minutes. Thus,in the conventional approaches, the UE has to restart the periodicregistration timer, whenever the data transmission occurs.

Consider another example scenario as depicted in FIG. 1B, wherein the UEperforms the periodic registration procedure using the periodicregistration timer and initiates the emergency service while theperiodic registration time is operating. The UE sends a periodicregistration request to the CN and receives a periodic registrationtimer value of 12 minutes (for example) from the CN. On receiving theperiodic registration timer value, the UE starts the PTAU timer byapplying the received periodic registration timer value (for example: 12mins), and the PTAU timer behaves as the periodic registration timer.

In an example herein, on starting the PTAU timer, the UE may operate inthe connected mode for 4 minutes. After 4 minutes, the UE may enter intothe idle mode. After 2 minutes, the UE exits from the idle mode andstarts data transmission by entering into the connected mode and entersinto the idle mode on completion of the data transmission. When the UEenters into the idle mode, the UE restarts the PTAU timer. Thus, thePTAU timer starts from a value of 0 again. After 3 minutes of restartingthe periodic registration timer, the UE may initiate/execute theemergency service by entering into an emergency registered state. Onlyon the completion of the emergency service, the UE enters into the idlemode. When the UE enters into the idle mode, the UE restarts the PTAUtimer. The UE may remain in the idle mode till the expiry of the PTAUtimer and will perform detach procedure on expiry of PTAU timer. In anexample herein, the UE may remain in the idle mode for 12 minutes, asthe PTAU timer expires by reaching the value of 12 minutes. Within 12minutes of time, the UE may receive the response/call back from the CNin response to the executed emergency service. Further, the UE performsa detach procedure to exit from the emergency state on the expiry of thePTAU timer. Thus for normal periodic timer the UE gets full 12 mins(PTAU timer value duration) to remain registered with the network toreceive any possible emergency call back from the network.

Consider an example scenario as depicted in FIG. 1C, wherein the UEperforms the periodic registration procedure using the periodicregistration timer with the “Strictly Periodic Registration TimerIndication”. The UE sends a periodic registration request to the CN andreceives a periodic registration timer value of 12 minutes (for example)from the CN. The periodic registration timer value indicates time valueat which the UE has to perform the periodic registration procedure withthe CN. On receiving the periodic registration timer value, the UEstarts executing/operating the PTAU timer by applying the receivedperiodic registration timer value (for example: 12 mins) with the“Strictly Periodic Registration Time Indication”. In an example, thePTAU behaves as the periodic registration timer with the “StrictlyPeriodic Registration Time Indication”, wherein the “Strictly PeriodicRegistration Time Indication” indicates that the PTAU timer does notrequire to re-start if the UE enters into the connected mode or the idlemode during the received periodic registration timer value (i.e. whilethe PTAU timer is operating).

In an example, on starting the PTAU timer, the UE remains in theconnected mode for 4 minutes and enter into the idle mode. After 2minutes of entering into the idle mode, the UE starts the datatransmission by entering into the connected mode. The UE may enter intothe idle mode on completion of the data transmission. The UE maycontinue the periodic registration timer without restating it when theUE enters into the idle mode. Further, after 3 minutes of entering intothe idle mode, the UE starts the data transmission by entering into theconnected mode. The UE may enter into the idle mode on completion of thedata transmission and remain in the idle mode till the expiry of thePTAU timer. In an example scenario, the UE may remain in the idle modefor 3 minutes, as the periodic registration timer expires after 3minutes of the UE entering into the idle mode (that is after 12 minutesof initiating the periodic registration timer). The expiry of theperiodic registration timer triggers the UE to perform the registrationprocedure. The UE strictly performs the registration procedure after 12minutes (i.e., after the expiry of the PTAU timer), irrespective of anumber of times the UE had been to the connected mode during the 12minutes duration. Thus, in the conventional approaches, the UEperforming periodic registration procedure with the “Strictly PeriodicRegistration Timer Indication” does not restart the timer on completingeach data transmission i.e. each time UE goes to connected mode the PTAUtimer is not stopped and neither started again when the UE goes back toIDLE mode.

Consider an example scenario as depicted in FIG. 1D, wherein the UEperforms the periodic registration procedure using the periodicregistration timer with the “Strictly Periodic Registration TimerIndication”. The UE sends a periodic registration request to the CN andreceives a periodic registration timer value of 12 minutes (for example)from the CN. On receiving the periodic registration timer value, the UEstarts executing/operating the PTAU timer by applying the receivedperiodic registration timer value (for example: 12 mins) with the“Strictly Periodic Registration Time Indication”. In an example, thePTAU timer behaves as the periodic registration timer with the “StrictlyPeriodic Registration Time Indication”.

In an example herein, on starting the PTAU timer, the UE remains in theconnected mode for 4 minutes and enters into the idle mode. After 2minutes of entering into the idle mode, the UE starts the datatransmission by entering into the connected mode. The UE may enter intothe idle mode on completion of the data transmission. The UE maycontinue the periodic registration timer without restarting it when theUE enters into the idle mode. Further, after 3 minutes of entering intothe idle mode, the UE executes the emergency service (for example, whenthe UE faces an authentication procedure failure) by entering into theemergency registered state. Once the emergency service is completed, theUE enters into the idle mode and remains in the idle mode until theexpiry of the periodic registration timer. In an example scenario, theUE will remain in the idle mode only for 3 minutes. The expiry of theperiodic registration timer triggers the UE to initiate thederegistration procedure. However, the duration/time in which the UE canremain in the idle mode has been drastically reduced due to the“Strictly Periodic Registration Timer Indication”. Therefore, the UE mayobtain a less period of time (in the current example, only 3 minuteswhen compared to 12 minutes as discussed in FIG. 1b ) for receiving theemergency response or call back from the core network (CN).

Further, according to the current 3GPP TS 24.501, the UE may perform aregistration procedure to access mission critical services (MCSs). TheUE sends a registration request message to the CN for an initialregistration for the MCSs. If the UE does not receive any response fromthe network, the UE enters into a 5GMMDEREGISTERED.REGISTRATION.ATTEMPTING-REGISTRATION state and starts atimer T3511. The UE re-starts the registration procedure after an expiryof a timer T3511 (for example; after 10 seconds). After a certain numberof unsuccessful attempts, the UE starts a timer T3502. On expiry of thetimer T3502 (for example: after 14 minutes), the UE initiates a nextregistration procedure. However, the UE may not able to initiate theregistration procedure on receiving a request for the MCSs when thetimer T3511 or T3503 is operating. Similarly, the MCSs are delayed, whenthe UE is in 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state andwhen the timer T3510 or T3502 is operating.

In addition, when a service request procedure fails a certain number oftimes after the registration procedure, the UE starts a T3525 timer. Insuch a case, the UE is not allowed to initiate the next service requestprocedure for the MCSs till an expiry of the T3525 timer. Further, theUE may start a T3346 timer on the successful service request procedure.In such a case, the UE may not able to initiate any mobility managementor connection management procedure till the expiry of the T3346 timer.

Thus, in the conventional approaches, the MCS is delayed for aconsiderable duration of time. This may lead to serious consequencesduring an emergency scenario.

FIGS. 2A, 2B, and 2C depict a wireless communication system/wirelessnetwork 200 for handling emergency services, wherein the wirelessnetwork 200 includes at least one non-public network, and at least onepublic network, according to an embodiment of the disclosure. Thewireless network 200 referred herein can be configured for handlingemergency services during an emergency event/scenario. The emergencyservices can support real-time, high priority total conversationservices such as, but not limited to, voice calls, video calls,real-time text messages, IP Multimedia Subsystem (IMS) emergency calls,or the like. Examples of the emergency event can be, but is not limitedto, a medical event, a criminal attack, a natural disaster, an accident,an injury, and so on.

The wireless network 200 includes at least one Public Land MobileNetwork (PLMN) 202, at least one non-public network (NPN) 204, and aplurality of User Equipments (UEs) 206. The PLMN 202 can be configuredto provide PLMN services to the UEs 206 in a specific region. The PLMNservices include normal communication services and the emergencyservices. Examples of the normal communication services can be, but isnot limited to, a streaming service (streaming of multimedia data suchas audio, video, text and so on), a file download service, a carouselservice (a service for combining file download service and streamingservice), a television (TV) service, an Internet Protocol (IP)Multimedia Subsystem (IMS) service, a non-3rd Generation PartnershipProject (non-3GPP) service (for example: firewalling or the like), ashort messaging service, a Multimedia Messaging Service (MMS), and soon. Examples of the emergency services can be, but is not limited to, anemergency call to local Fire/Ambulance/Police stations, an IMS call,text messages, and so on. The PLMN 202 can be operated by a mobilenetwork operator (MNO) and can be identified using a PLMN_identifier(PLMN_ID). Embodiments herein use the terms such as “PLMN”, “cellularnetwork”, “public network”, “3GPP access network”, and so oninterchangeably to refer to a network that provides the emergencyservices, and the normal communication services in a given region.

As depicted in FIG. 2B, the PLMN 202 includes one or more differentpublic cellular networks/Radio Access Technologies (RATs) 202 a such,as, but not limited to, a Long Term Evolution (LTE) network, an advancedLTE network, a New Radio (NR)/5G network, a Narrowband Internet ofThings (NB-IoT), a Universal Mobile Telecommunications Service (UMTS), aGlobal System for Mobile Communications (GSM) Enhanced Data rates forGSM Evolution (EDGE) Radio Access Network (GERAN) system or any othernext generation networks.

As depicted in FIG. 2C, a RAT 202 a of the PLMN 202 may include aplurality of Radio Access Networks (RANs)/public RANs 202 b, and atleast one Core Networks (CN) 202 c. The RAN 202 b and the CN 202 c maycomprise of one or more processors/Central Processing Units (CPUs), amemory, a storage, a transceiver, and so on, for performing at least oneintended function/operation. The RAN 202 b may comprise of nodes/BaseStations (BSs) such as, but not limited to, evolved nodes (eNBs), NewRadio nodes (gNBs), and so on. The RAN 202 b can be configured toconnect the at least one UE 206 to the CN 202 c. The RAN 202 b can beconfigured to perform radio resource management functions such as, butnot limited to, radio bearer control, radio admission control,connection mobility control, dynamic allocation of resources to the UE206 in uplink/downlink (scheduling), and so on. Embodiments herein usethe terms such as “RAN”, “public RAN”, “PLMN RAN”, “public cell”, and soon interchangeably to refer to an access node of the PLMN 202 thatconnects the UEs 206 to the at least one CN 202 c.

The CN 202 c referred herein can be at least one of an Evolved PacketCore (EPC), a 5G core (5GC) network, or the like. The CN 202 c can beconnected to the RAN 202 b and an external data network. Examples of theexternal data network can be, but not limited to, the Internet, a PacketData Network (PDN), an Internet Protocol (IP) Multimedia Core NetworkSubsystem, and so on. The CN 202 c can be configured to connect the UEs206 (that are connected to the associated RAN 202 b) to the externaldata network for the communication services or the emergency services.Embodiments herein use the terms such as “CN”, “public CN”, “PLMN CN”,and so on interchangeably to refer to a core network of the PLMN 202that connects the UEs 206 to the external data network. In an example,as depicted in FIG. 2C, the PLMN 202 includes a 5G system (5GS) 202 aand a LTE network 202 b. The 5GS includes one or more gNBs/public cells202 b connected to a 5GC network 202 c. The LTE network 202 b includesone or more eNBs/public cells connected to an EPC network 202 c.

The NPN(s) 204 can be configured to provide coverage and privateservices to the UEs 206 present within a location/premises such as, butis not limited to, an organization, an enterprise, an industry/factory,a campus, a room, a floor, a hospital, a stadium, an airport, a shoppingcenter, and so on. The private services can include services that aredefined by the respective premises. Examples of the private services canbe, but is not limited to, a streaming service (streaming of multimediadata such as audio, video, text and so on), a file download service, amission-critical service (for example; autonomous driving, control of asmart grid, smart operation of industrial automation processes, or anyother service which requires different levels of security), and so on.The NPN 204 can be deployed as a non-standalone NPN, or a standalone NPN(SNPN). The non-standalone NPN can be deployed in conjunction with thePLMN 202 using a network slicing and/or a Closed Access Group (CAG) cell(as specified in 3GPP TS 23.501). The network slicing provides dedicateddata network names (DNNs) networks, or one or more network sliceinstances that can make the NPN 204 available to the UEs 206 via thePLMN 202. The stand-alone NPN may be deployed without requiring thesupport of the PLMNs 202. The stand-alone NPN may use the CAG and/or anon-public network identifier to identify a group of subscribers/UEs,who are permitted to access the NPN. The CAG may be used by the NPN 204to prevent users/UEs from automatically selecting and registering from alocation/region/area, which does not provide access to the NPNs 204 forthe UEs 206. The CAG may be used by the NPN 204 to prevent users/UEsfrom automatically selecting and registering from alocation/region/area, where the UEs 206 are not allowed to access theNPNs 204. The NPN can be assigned a CAG Identifier (CAG ID) to identifyit. Embodiments herein use the terms “CAG Identifier” and “non-publicnetwork identifier” interchangeably to refer to the CAG ID. The CAG IDcan be the CAG-ID and/or NPN-ID. Embodiments herein use the terms suchas, but not limited to, “NPN”, “private network”, “public networkintegrated NPN”, “non-3GPP access network”, “SNPN”, “CAG cells”, and soon interchangeably to refer to a network that confines the communicationservices within boundaries of the defined premises for the UEs 206.Embodiments herein are further explained considering the NPN 204 as theSNPN for example, but it may be obvious to a person skilled in the artthat the non-standalone NPN can also be considered.

As depicted in FIG. 2B, the NPN 204 includes at least one non-public RAN204 a, and a non-public Core Network (CN) 204 b. The non-public RANreferred herein can be a CAG cell including at least one of 3GPP accessnodes, non-3GPP access nodes, and so on. Examples of the 3GPP accessnodes can be, but not limited to, eNBs, gNBs, and so on. Examples of thenon-3GPP access nodes can be, but is not limited to, a Local AccessNetwork (LAN) node, a Wireless LAN (WLAN) node, a Wi-Fi node, and so on.The non-public RAN 204 a can be configured to broadcast CAG IDs of theNPN 204 to the UEs 206. The UE 206 can identify and connect to thecorresponding NPN 204 using the broadcasted CAG IDs, if the broadcastedCAG ID is present in an allowed list of CAG IDs configured for the UE206. In an embodiment, the non-public RAN 204 a can be configured toconnect the UE 206 to the non-public CN 204 b. In an embodiment, the NPN204 can share the non-public RAN 204 a with the PLMN 202 by assigningits own cell identities and tracking area codes to the non-public RAN204 a. In such a case, the non-public RAN of the NPN 204 can be a RAN ofthe PLMN 202 including an assistance of the CAG IDs. Embodiments hereinuse the terms such as “non-public RAN”, “CAG cell RAN”, “CAG cell”,“SNPN RAN”, “non-public/SNPN BS”, “private RAN/BS”, and so oninterchangeably to refer to a node that broadcasts the CAG IDs to the UE206 and connects the authorized UE 206 to the PLMN 202.

The non-public CN 204 b referred herein can be at least one of an EPCnetwork, a 5GC network, or the like. The non-public CN 204 b can beconnected to the non-public RAN 204 a, a private data network/privateenterprise network, and the CN 202 c of the PLMN 202. The private datanetwork/private enterprise may be operated by at least one of theenterprise, the organization, the industry, an external entity, or thelike. Examples of the private data network can be, but is not limitedto, an Intranet, a cloud platform, a server, and so on. In anembodiment, the non-public CN 204 b can be configured to connect the UE206 (that is connected to the non-public RAN 204 a) to the private datanetwork for the private services defined within the premises. In anembodiment, the non-public CN 204 b can also be configured to connectthe UE 206 (that is connected to the non-public RAN 204 a) to the PLMN202 for the PLMN services (i.e., the normal communication services andthe emergency services). In an embodiment, the NPN 204 can share controlplane functionalities of the non-public CN 204 b with the PLMN 202.Embodiments herein use the terms such as “non-public CN”, “private CN”,and so on interchangeably to refer to a core network of the NPN 204.

In an embodiment, the NPN 204 including the CAG cell/non-public RAN 204a and the non-public CN 204 b may be referred hereinafter as the CAGcell 204 through the document.

As depicted in FIGS. 2A-2C, the UE(s) 206 can be a user device that iscapable of supporting the PLMN 202 and the NPN/CAG cell 204. Examples ofthe UE 206 can be, but is not limited to, a mobile phone, a smartphone,a tablet, a phablet, a personal digital assistant (PDA), a laptop, acomputer, a wearable computing device, a vehicle infotainment device, anInternet of Things (IoT) device, a Virtual Reality (VR) device, aWireless Fidelity (Wi-Fi) router, a USB dongle, a sensor, a robot, anauto-guided vehicle, and so on. The UE 206 can include one or moreprocessors/Central Processing Units (CPUs), a memory, a transceiver, andso on, for performing at least one intended function/operation.

The UE 206 can be configured to register with the PLMN 202 (that can bea home PLMN (HLPMN)) and obtain the allowed list of CAG IDs/permissionto access the CAG cells 204 and other permission/subscription detailsfrom the PLMN 202, wherein the CAG IDs identify the CAG cells 204. TheUE 206 can select the CAG cell based on the received allowed list of CAGIDs for accessing the private services and for connecting to the PLMN202 for the PLMN services. The UE 206 can automatically select theNPN/CAG cell 204 corresponding to one of the received allowed list ofCAG IDs that is available in the location. The UE 206 can also providethe received allowed list of CAG IDs to the user and allow the user toselect the NPN/CAG cell 204 corresponding to one of the allowed list ofCAG IDs.

In an embodiment, the UE 206 can be configured to operate in a CAG onlymode/CAG only feature. In the CAG only mode operation, the UE 206 canconnect only to the allowed CAG cell 204 to access the PLMN 202 for thePLMN services. Embodiments herein use the terms such as “CAG only mode”,“NPN access mode”, “SNPN access mode”, “SNPN support capability” and soon interchangeably to refer to a mode/state in which the UE 206 can onlyconnect to the NPN/CAG cell 204.

In order to operate in the CAG only mode, the UE 206 sends aregistration request to the CN 202 c of the PLMN 202 through the publicRAN 202 b that supports the CAG cell. The public RAN 202 b can bereferred herein after as a non-CAG cell 202 b through the document.Embodiments herein use the terms such as “non-CAG cell”, “non-CAG RAN”,“RAN”, “public RAN”, “PLMN RAN”, “public cell”, and so on,interchangeably through the document. The non-CAG cell/RAN 202 b can bea public cell/RAN, which can be accessed by the UE 206 to obtain thenormal communication service (for example: IMS voice call, internetservices, and so on) provided by the public PLMN 202. The registrationrequest may specify the CAG cell 204 selected by the UE 206 to connectand other permission/subscription details of the UE 206. The CN 202 c ofthe PLMN 202 checks if the UE 206 has the permissions to connect to theselected CAG cell 204 based on the allowed list of CAG IDs configuredfor the UE 206 (according to 3GPP TS 24.501 specification). If the UE206 has the permissions to connect to the selected CAG cell 204, the CN202 c of the PLMN 202 sends a registration accept message including anindicator, which can indicate to the UE 206 to operate in the CAG onlymode.

The UE 206, which is enabled to operate in the CAG only mode, caninitiate the emergency services in the emergency scenarios where theauthentication of the UE 206 fails or the authentication of the UE 206may not be performed. In an embodiment, the UE 206 can complete/performthe emergency services on the connected CAG cell 204, if the connectedCAG cell 204 supports the emergency services. In such a case, theconnected CAG cell 204 allows the UE 206 to connect to the CN 202 b forperforming/completing the emergency services.

In an embodiment, the UE 206 can be configured to operate in anemergency mode on initiating the emergency services. In an embodiment,the UE 206 can be configured to operate in the emergency mode, if theconnected CAG cell 204 does not support the initiated emergency servicesor if the CAG cells 204 are not available in the location of the UE 206when the UE 206 initiates the emergency services. In the emergency mode,the UE 206 connects to at least one non-CAG cell/public RAN 202 b of thePLMN 202 for availing the emergency services. The emergency mode can bea limited mode that is enabled only on the initiation of the emergencyservices. Further, performing the emergency services in the emergencymode can be subjected to local regulation.

In order to be operated in the emergency mode, the UE 206 disables theCAG only mode (i.e. deselects the connected CAG cell for the emergencyservice) and sends an indication to the CN 202 c of the PLMN 202indicating that the UE 206 is not operating in the CAG only mode. Onreceiving the indication, the CN 202 c of the PLMN 202 enables the UE206 to operate in the emergency mode.

In the emergency mode, the UE 206 determines the one or more non-CAGcells 202 b of the PLMN 202 available in the location of the UE 206based on signals broadcasted by the one or more non-CAG cells 202 b ofthe PLMN 202. The UE 206 selects the non-CAG cell 202 b from thedetermined one or more non-CAG cells 202 b that connects to the at leastone CN 202 c of the PLMN 202. The UE 206 attaches to the selectednon-CAG cell 202 b by establishing a Radio Resource Control (RRC)connection with the selected non-CAG cell 202 b. On attaching to theselected non-CAG cell 202 b, the UE 206 performs an emergency attachprocedure with the CN 202 c of the selected non-CAG cell 202 b andestablishes an emergency Protocol Data Unit (PDU) session with theexternal data network through the CN 202 c. The UE 206 performs theemergency service over the established emergency PDU session. In anembodiment, in a 5G network, the emergency attach procedure may bereferred to a registration performed with 5GS registration type“emergency registration” in the REGISTRATION REQUEST message. In anembodiment, in an Evolved Packet System (EPS)/LTE, the emergency attachprocedure may be referred to attached for emergency bearer services. TheUE 206 may be attached for the emergency bearer services, if the UE 206has only a Public Data Network (PDN) connection for the establishedemergency bearer services.

In an embodiment, the UE 206 may establish the PDU session with theconnected CAG cell 204 for performing the initiated emergency service.The UE 206 then selects the non-CAG cell 202 b for completing theinitiated emergency service.

In an embodiment, the CN 202 c of the PLMN 202 enables the UE 206 toswitch into the emergency mode from the CAG only mode, when the UE 206loses the connection with the CAG cell 204 during an ongoing emergencyservice or when the emergency service is established. In the emergencymode, the CN 202 c may handover the UE 206 from the connected CAG cell204 to the non-CAG cell 202 b of the PLMN 202 for completing theon-going/established emergency service.

On completion or release of the emergency service, the UE 206 entersinto an idle mode and remains in the idle mode for a pre-defined periodof time. In an embodiment, the period of time/value of the time can bepre-defined based on an implementation of the UE 206. In an example, theUE 206 may define the period of time in such a way that the period oftime has to be long enough in case an emergency personal wants tore-initiate the emergency service with the user of the UE 206, if theinitiated emergency service by the user of the UE 206 is dropped. In theidle mode, the UE 206 does not establish the RRC connection with any ofthe CAG cell 204 or the non-CAG cell 202 b. Once the pre-defined periodof time has passed, the UE 206 enables the CAG only mode automaticallyor by performing a registration update procedure with the CN 202 c ofthe PLMN 202.

FIGS. 2A, 2B, and 2C depict exemplary units/components of the wirelessnetwork 200, but it is to be understood that other embodiments are notlimited thereon. In other embodiments, the wireless network 200 mayinclude less or a greater number of units. Further, the labels or namesof the units are used only for illustrative purpose and does not limitthe scope of the embodiments herein. One or more units can be combinedtogether to perform same or substantially similar function in thewireless network 200.

FIG. 3 depicts the UE 206 configured to perform the emergency servicesby camping on the non-CAG cell 202 a, according to an embodiment of thedisclosure.

The UE 206 includes a memory 302, a communication unit 304, a display306, and a controller 308. The UE 206 can also include at least onetransceiver, a processing circuitry, a storage unit, an input/output(I/O) module, and so on (not shown).

The memory 302 can store at least one of the PLMN IDs, the allowed listof CAG IDs, and so on. Examples of the memory can be, but not limitedto, NAND, embedded Multi Media Card (eMMC), Secure Digital (SD) cards,Universal Serial Bus (USB), Serial Advanced Technology Attachment(SATA), solid-state drive (SSD), and so on. Further, the memory 302 mayinclude one or more computer-readable storage media. The memory 302 mayinclude one or more non-volatile storage elements. Examples of suchnon-volatile storage elements may include magnetic hard discs, opticaldiscs, floppy discs, flash memories, or forms of electricallyprogrammable memories (EPROM) or electrically erasable and programmable(EEPROM) memories. In addition, the memory 302 may, in some examples, beconsidered a non-transitory storage medium. The term “non-transitory”may indicate that the storage medium is not embodied in a carrier waveor a propagated signal. However, the term “non-transitory” should not beinterpreted to mean that the memory 302 is non-movable. In certainexamples, a non-transitory storage medium may store data that can, overtime, change (e.g., in Random Access Memory (RAM) or cache).

The communication unit 304 can be configured to enable the UE 206 toconnect with at least one of the NPN/CAG cell 204, and the PLMN 202 overan interface. Examples of the interface can be, but is not limited to, awired interface, a wireless interface (for example: an air interface, anNu interface, or the like), a wireless fronthaul interface, a wired orwireless backhaul interface, or any structure supporting communicationsover a wired or wireless connection.

The display 306 can be configured to enable the user to interact withthe UE 206. The display 306 can also be configured to display thePLMN_IDs and the CAG IDs to the user. The display 306 can also beconfigured to allow the user to select the PLMN 202 corresponding to oneof the PLMN IDs and the CAG cell 204, corresponding to one of the CAGIDs.

The controller 308 can be at least one of a single processer, aplurality of processors, multiple homogeneous or heterogeneous cores,multiple Central Processing Units (CPUs) of different kinds,microcontrollers, special media, and other accelerators. The controller308 can be configured to handle the emergency services by enabling theUE 206 to camp onto the at least one non-CAG cell 202 b of the PLMN 202.

The controller 308 includes a reception module 308 a, a CAG-only modeenabling module 308 b, an emergency mode enabling module 308 c, and amode switching module 308 d.

The reception module 308 a can be configured to receivesubscription/permission details from the PLMN 202, whilesubscribing/registering with the PLMN 202. The permission details canbe, but not limited to, the allowed list of CAG IDs/allowed CAG list(i.e. a list of CAG Identifiers corresponding to the NPN/CAG cells 204that the UE 206 is allowed to access); and optionally, a CAG-onlyindication whether the UE 206 is only allowed to access the PLMN 202 viathe CAG cells 204 (according to 3GPP TS 38.304). The reception module308 a stores the received permission details in the memory 302.

The CAG-only mode enabling module 308 b can be configured to enable theUE 206 to operate in the CAG only mode. In the CAG only mode, the UE 206can connect only to the CAG cell 204 to access the at least one CN 202 cof the PLMN 202 for the normal communication services and/or theemergency services. The CAG-only mode enabling module 308 b can performthe registration procedure with the at least one CN 202 c of the PLMN202 for enabling the UE 206 to operate in the CAG only mode, accordingto the 3GPP TS 24.501.

For enabling the UE 206 to operate in the CAG only mode, the CAG-onlymode enabling module 308 b uses the received allowed list of CAG IDs forselecting the at least one CAG cell 204 automatically or manually (i.e.allowing the user to select one of the CAG IDs corresponding to the CAGcell). The CAG-only mode enabling module 308 b sends a registrationrequest in a Non-Access Stratum (NAS) message to the CN 202 c throughthe associated public-RAN 202 b to enable the UE 206 to operate in theCAG only mode. The CN 202 c verifies if the UE 206 is allowed to accessthe selected CAG cell 204 using the maintained permission details of theUE 206 (i.e. according to the 3GPP TS 24.501). If the UE 206 is allowedto access the selected CAG cell 204, the CN 202 c of the PLMN 202 sendsa registration accept in the NAS message with the indication to the UE206. The indication indicates to the UE 206 that the UE is to operate inthe CAG only mode. Thereby, the UE 206 can connect only to the CAG cell204 for accessing the at least one CN 202 c of the PLMN 202.

The emergency mode enabling module 308 c can be configured to enable theUE 206 to operate in the emergency mode on initiating the emergencyservices. In an embodiment, in the emergency mode, the UE 206 canconnect to any one of the non-CAG cells/public RANs 202 b of the PLMN202 to access any one of the CNs 202 c of the PLMN 202. In anembodiment, the emergency mode enabling module 306 can enable the UE 206to operate in the emergency mode, if the connected CAG cell does notsupport the initiated emergency services. In an embodiment, theemergency mode enabling module 306 can enable the UE 206 to operate inthe emergency mode, if the UE 206 is not able to identify and connect tothe CAG cell 204 available at the location for performing the initiatedemergency services.

The emergency mode enabling module 308 c may receive a request from theuser through the display 306 for the emergency service (for example; tomake a call to ambulance). In response to the received request, theemergency mode enabling module 308 c initiates the requested emergencyservice. On initiating the requested emergency service, the UE 206disables the CAG only mode by allowing the UE 206 to locally detach fromthe connected CAG cell 204, thereby the UE 206 enters into the emergencymode.

On disabling the CAG only mode, the emergency mode enabling module 308 cdetermines/searches for the one or more non-CAG cells 202 b of the PLMN202 that are available in the location of the UE 206. The emergency modeenabling module 308 c determines the one or more non-CAG cells 202 bbased on the signals broadcasted by the one or more non-CAG cells 202 b.The emergency mode enabling module 308 c then selects the non-CAG cell202 b from the determined one or more non-CAG cells 202 b based on atleast one factor. Examples of the factor can be, but not limited to,signal strength, reference signal strength power (RSRP), and so on.

Once the non-CAG cell 202 b of the PLMN 202 is selected, the emergencymode enabling module 308 c enables the UE 206 to connect to/camp on tothe selected non-CAG cell 202 b. The emergency mode enabling module 308c further enables the UE 206 to establish the RRC connection with thecamped non-CAG cell 202 b. The non-CAG cell 202 b connects the UE 206 tothe associated CN 202 c in the PLMN 202. The emergency mode enablingmodule 308 c then enables the UE 206 to perform the emergency attachprocedure with the CN 202 c through the connected non-CAG cell 202 b. Inthe emergency attach procedure, the emergency mode module 3038 c enablesthe UE 206 to send an emergency attach request to the CN 202 c throughthe connected non-CAG cell 202 b. The CN 202 c establishes the emergencyPDU session between the external data network and the UE 206 withoutauthenticating the UE 206, as it receives the emergency attach request.Once the emergency PDU session is established, the emergency modeenabling module 308 c enables the UE 206 to perform the initiatedemergency service over the established PDU session. Thus, the UE 206supporting the CAG only mode can perform the emergency services usingthe non-CAG cells 202 b.

The mode switching module 308 d can be configured to enable the UE 206to enter into the idle mode on completion of the initiated emergencyservice using the non-CAG cell 202 b. In the idle mode, the UE 206 cansupport the CN 202 c of the PLMN 202. The mode switching module 308 dcan enable the UE 206 to remain in the idle mode for the pre-definedperiod of time. On the expiry of the pre-defined period of time, themode switching module 308 d enables the CAG only mode for the UE 206. Inan embodiment, the mode switching module 308 d enables the CAG only modeby itself that is without communicating with the PLMN 202. In anembodiment, the mode switching module 308 d enables the CAG only mode byperforming the registration updating procedure with the CN 202 c of thePLMN 202.

FIG. 3 depicts exemplary units/components of the UE 206 configured forperforming the emergency services using the non-CAG cells 202 b, but itis to be understood that other embodiments are not limited thereon. Inother embodiments, the UE 206 may include less or a greater number ofunits. Further, the labels or names of the units are used only forillustrative purpose and does not limit the scope of the embodimentsherein. One or more units can be combined together to perform same orsubstantially similar function in the UE 206.

FIGS. 4A and 4B depict an example scenario of handling the emergencyscenarios in the wireless network 200, according to an embodiment of thedisclosure. Consider an example scenario, wherein the PLMN 202 includesa 5G system (5GS) 202 a, and an LTE system/Evolved Packet System (EPS)202 a and the at least one CAG cell/NPN 204 is connected to the 5GS 202a. The 5GS 202 a includes one or more gNBs/non-CAG cells 202 b connectedto the 5GC network 202 c, and the LTE system 202 a includes the one ormore non-CAG cells 202 b connected to the EPC network 202 c. The 5GC 202c may include an access and mobility management function (AMF) 402, andother modules such as, but not limited to, an authentication serverfunction (AUSF), a unified data management (UDM), and so on forperforming the at least one intended function. The AMF 402 is configuredto support functions such as, but not limited to, termination of NASsignaling, NAS ciphering and integrity protection, registrationmanagement, connection management, mobility management, accessauthentication and authorization, security context management, and soon.

In such a scenario, the UE 206 initiates the registration procedure withthe 5GC 202 c, such that the UE 206 operates in the CAG only mode. TheUE 206 selects the CAG cell 204 for which the UE has the permissions toaccess. Thereafter, the UE 206 sends the registration request in the NASmessage to the AMF 402 of the 5GC 202 c through one of the gNBs/non-CAGcell 202 b for configuring the UE 206 to operate in the CAG only mode.The AMF 402 may verify the permissions of the UE 206 to allow theselected CAG cell and configure the UE 206 to operate in the CAG onlymode when the UE 206 has the permissions to access the selected CAG cell204. Thus, in the CAG only mode, the UE 206 can connect only to the CAGcell 204 to access the 5GS 202 a of the PLMN 202 for the 5GS/PLMNservices.

The UE 206, configured to operate in the CAG only mode, may initiate theemergency services during the emergency event. In an example herein,consider that the UE 206 supporting the CAG only mode receives a requestfrom the user to make an emergency call to a fire station and the UE 206does not find the CAG cell 206 to perform the emergency call. In such ascenario, embodiments herein enable the UE 206 to disable the CAG onlymode and to connect to the one of the non-CAG cells 202 b of the PLMN202 to perform the emergency call.

For performing the emergency call, the UE 206 performs a search todetermine the available non-CAG cells 202 b of the PLMN 202 in thelocation of the UE 206, wherein non-CAG cells 202 b may connect to the5GC 202 c of the 5GS 202 a or to the EPC 202 c of the LTE. In an exampleherein as depicted in FIG. 4A, consider that the UE 206 determines thenon-CAG cell/gNB 202 b connected to the 5GC 202 c and selects thedetermined non-CAG cell 202 b for performing the emergency call. The UE206 connects to/camp on to the selected non-CAG cell/gNB 202 b. The UE206 performs the emergency attach procedure with the AMF 402 of the 5GC202 c through the connected non-CAG cell/gNB 202 b and establishes theemergency PDU session with the external data network through the 5GC 202c. On establishing the PDU session, the UE 206 can perform the emergencycall to the fire exchange over the established emergency PDU session.

In an example herein as depicted in FIG. 4B, consider that the UE 206determines the non-CAG cell s/eNBs 202 b connected to the EPC 202 c andselects the one of the determined non-CAG cell s/eNBs 202 b based on theassociated signal strength for performing the emergency call. The UE 206connects to/camp on to the selected non-CAG cell/eNB 202 b. The UE 206performs the emergency attach procedure with the EPC 202 c through theconnected non-CAG cell/eNB 202 b and establishes the emergency PDUsession with the external data network through the EPC 202 c. Onestablishing the PDU session, the UE 206 can perform the emergency callto the fire station over the established emergency PDU session. Thus,the UE 206, configured to operate in the CAG only mode, can also camp onthe non-CAG cells (supporting different RATs) only during the emergencyevents for performing the emergency services.

FIG. 5 is an example sequence diagram depicting the handling of theemergency service using the non-CAG cells 202 b, according to anembodiment of the disclosure. In an example herein, consider that theCAG cell/NPN 204 is connected to the 5GS of the PLMN 202. The 5GS of thePLMN 202 includes a plurality of non-CAG cells/gNBs 202 b, and the 5GC202 c.

At step 501, the UE 206 registers with the AMF 402 of the 5GC 202 c tobe configured to operate in the CAG only mode. In the CAG only mode, theUE 206 can connect only to the CAG cell 204 to access the 5GC 202 c.

At step 502, the UE 206 receives a request from the user for theemergency service. In such a case, the UE 206 disables the CAG onlymode. The UE 206 may select any one of the non-CAG cells that areavailable in the location of the UE 206, wherein the non-CAG cells canbe gNBs or eNBs connecting to the 5GC or the EPC. In an example herein,the UE 206 may select any one of the non-CAG cell/gNBs 202 b of the 5GS202 a that are available in the location of the UE 206. The UE 206 campsonto the selected non-CAG cell/gNB 202 b for initiating the emergencyservice. The UE 206 performs the emergency attach procedure with the AMF402 of the 5GC 202 c that is connected to the camped non-CAG cell/gNB202 b and establishes the PDU session with the external data networkthrough the 5GC 202 c. The UE 206 thereafter can perform the emergencyservices over the established PDU session.

At step 503, the UE 206 enters into the idle mode on therelease/completion of the initiated emergency service. The UE 206remains in the idle mode for the pre-defined period of time. On theexpiry of the pre-defined time, at step 504, the UE 206 again enablesthe CAG only mode by itself or by performing the registration updateprocedure with the AMF 402 of the 5GC 202 c.

FIG. 6 is an example sequence diagram depicting the handling of theemergency service using the non-CAG cells 202 b in the wireless network200 that includes the SNPN 204, according to an embodiment of thedisclosure. In an example herein, consider that the wireless network 200includes the SNPN 204 as the NPN 204. The SNPN 204 can connect to the5GS 202 a. The UE 206 can support the SNPN 204 and the PLMN 202. In sucha case, at step 601, the UE 206 registers with the SNPN 204 and campsonto the SNPN cells/CAG cells for accessing the 5GC 202 a (i.e.,configured to operate in the SNPN access mode (CAG only mode)).

At step 602, the UE 206 receives a request from the user for theemergency service. In such a case, the UE 206 disables the SNPN accessmode by disabling an Access Stratum (AS) layer and NAS capabilityrelated to SNPN. The UE 206 may select any one of the non-CAG cells thatare available in the location of the UE 206, wherein the non-CAG cellscan be gNBs or eNBs connecting to the 5GC or the EPC. In an exampleherein, consider that the UE 206 may select any one of the non-CAGcell/gNBs 202 b of the 5GS 202 a that are available in the location ofthe UE 206. The UE 206 camps onto the selected non-CAG cell/gNB 202 bfor initiating the emergency service. The UE 206 performs the emergencyattach procedure with the AMF 402 of the 5GC 202 c that is connected tothe camped non-CAG cell/gNB 202 b and establishes the PDU session withthe external data network through the 5GC 202 c. The UE 206 thereaftercan perform the emergency services over the established PDU session.

At step 603, the UE 206 enters into the idle mode on therelease/completion of the initiated emergency service. The UE 206remains in the idle mode for the pre-defined period of time. Once thepre-defined period of time has passed, at step 604, the UE 206 againenables the SNPN access mode.

FIG. 7 is a flow diagram 700 depicting a method for handling theemergency services in the wireless network 200 including the NPN 204 andthe PLMN 202, according to an embodiment of the disclosure.

At step 702, the method includes initiating, by the UE 206, the at leastone emergency service while operating in the CAG only mode. In the CAGonly mode, the UE 206 access only the at least one CAG cell/NPN 204.

At step 704, the method includes selecting, by the UE 206, the non-CAGcell 202 b from the plurality of CAG cells in the PLMN. The non-CAG cell202 b can be a public RAN that provides the normal communicationservices and the emergency services to the UE 206 by supporting the atleast one CAG cell 204. The UE 206 can perform the initiated at leastone emergency service by establishing the PDU session or by establishingthe emergency attach procedure with the non-CAG cell 202 b. The variousactions in method 700 may be performed in the order presented, in adifferent order or simultaneously. Further, in some embodiments, someactions listed in FIG. 7 may be omitted.

FIGS. 8A and 8B depict another wireless network/wireless communicationsystem 800 for handling the emergency services while performing periodicregistration procedures, according to an embodiment of the disclosure.The wireless network 800 referred herein can be configured for handlingemergency services while performing periodic registration procedures byat least one UE. The emergency services can support real-time, highpriority total conversation services such as, but not limited to, voicecalls, video calls, real-time text messages, IP Multimedia Subsystem(IMS) emergency calls, or the like. Examples of the emergency event canbe, but is not limited to, a medical event, a criminal attack, a naturaldisaster, an accident, an injury, and so on. The periodic registrationprocedure may be performed to update location information of the atleast one UE and mobility registered state with the network 800 fortracking the at least one UE.

The wireless network 800 includes at least one PLMN 802 and a pluralityof UEs 804. The PLMN 802 can be configured to provide PLMN services tothe UEs 804 in a specific region. The PLMN services includecommunication services and emergency services. Examples of thecommunication services can be, but is not limited to, a streamingservice (streaming of multimedia data such as audio, video, text and soon), a file download service, a carousel service (a service forcombining file download service and streaming service), a television(TV) service, an Internet Protocol (IP) Multimedia Subsystem (IMS)service, a non-3rd Generation Partnership Project (3GPP) service (forexample: firewalling or the like), a short messaging service, aMultimedia Messaging Service (MMS), and so on. Examples of the emergencyservices can be, but not limited to, emergency calls to localFire/Ambulance/Police stations, IMS calls, text messages, and so on. ThePLMN 802 can be operated by a mobile network operator (MNO) and can beidentified using a PLMN_identifier (PLMN_ID). Embodiments herein use theterms such as “PLMN”, “cellular network”, “public network”, “3GPP accessnetwork”, and so on, interchangeably to refer to a network that providesthe emergency services, and the communication services to public use ina given region.

The PLMN 802 includes one or more different public cellularnetworks/RATs 806 such, as, but not limited to, a Long Term Evolution(LTE) network, an advanced LTE network, a New Radio (NR)/5G network, aNarrowband Internet of Things (NB-IoT), a Universal MobileTelecommunications Service (UMTS), a Global System for MobileCommunications (GSM) Enhanced Data rates for GSM Evolution (EDGE) RadioAccess Network (GERAN) system or any other next generation networks. TheRATs 806 includes a plurality of RANs 806 a, and at least one CN 806 b.The RAN 806 a and the CN 806 b may comprise of one or moreprocessors/Central Processing Units (CPUs), a memory, a storage, atransceiver, and so on, for performing at least one intendedfunction/operation.

The RAN 806 a may comprise of nodes/Base Stations (BSs) such as, but notlimited to, evolved nodes (eNBs), New Radio nodes (gNBs), a new radioaccess network supporting both an eNB, and a gNB, and so on. The RAN 806a can connect the at least one UE 804 to the at least one CN 806 b. TheRAN 806 a can be configured to perform radio resource managementfunctions such as, but not limited to, radio bearer control, radioadmission control, connection mobility control, dynamic allocation ofresources to the UE in uplink/downlink (scheduling), and so on.

The CN 806 b referred herein can be at least one of an Evolved PacketCore (EPC), a 5G core (5GC) network, or the like. The CN 806 b can beconnected to the RAN 806 a and an external data network. Examples of theexternal data network can be, but not limited to, the Internet, a PacketData Network (PDN), an Internet Protocol (IP) Multimedia Core NetworkSubsystem, and so on. The CN 806 b can be configured to connect the atleast one UE 804 to the external data network for the communicationservices or the emergency services. In an example, as depicted in FIG.8B, the PLMN 802 includes a 5G system (5GS) 806 and a LTE network 808.The 5GS 806 includes a plurality of gNBs/RANs 806 a connected to atleast one 5GC 806 b. The LTE network 808 includes a plurality ofeNBs/RANs 806 a connected to at least one EPC 806 b.

The UE(s) 804 can be a user device that is capable of supporting thePLMN 802. Examples of the UE 804 can be, but is not limited to, a mobilephone, a smartphone, a tablet, a phablet, a personal digital assistant(PDA), a laptop, a computer, a wearable computing device, a vehicleinfotainment device, an Internet of Things (IoT) device, a VirtualReality (VR) device, a Wireless Fidelity (Wi-Fi) router, a USB dongle, asensor, a robot, an auto-guided vehicle, and so on. The UE 804 caninclude one or more processors/Central Processing Units (CPUs), amemory, a transceiver, and so on, for performing at least one intendedfunction/operation. In an embodiment, the UE 804 can be configured tooperate in a Mobile Initiated Connection Only (MICO) mode by registeringwith the CN 806 b of the PLMN 802. The UE 804 may operate in the MICOmode, when the UE 804 wants to perform only an uplink data transfer.Thus, in the MICO mode, the UE 804 can only send data (for example: textmessages, media (for example; audio, video, images, and so on), sensordata, and so on)) to the at least one CN 806 b of the PLMN 802 withoutreceiving any downlink data from the CN 806 b. Thus, in the MICO mode,the CN 806 b does not perform paging for the UE 804.

In an embodiment, the UE 804 has to perform a registration managementprocedure and a signaling/connection management procedure in order toregister location information and ensure that information about wherethe UE 804 is currently located is continuously up-to-date and correctin the location registers of the PLMN 802. Thus, the CN 806 b can trackthe UE 804 continuously. In an embodiment, the UE 804 performs theregistration and connection management procedures according to 3GPP23.501 subclause 5.3.7.

The UE 804 performs the registration management procedure toregister/de-register with the at least one CN 806 b of the PLMN 802 andestablish UE context in the CN 806 b. The UE 804 performs a registrationprocedure to register with the CN 806 b to receive the services thatrequires registration. On registering with the CN 806 b, if applicable,the UE can update its registration to the CN 806 b to periodicallymaintain reach ability/location (i.e., periodic registration update), orupdate its capability or re-negotiate protocol parameters upon movement(mobility registration update). Further, the UE 804, and the CN 806 buses two states; a de-registered state(RM-DEREGISTERED/5GMM-DEREGISTERED state) and a registered state(RM-REGISTERED/5GMM-REGISTERED state); that reflect a registrationstatus of the UE 804 in the PLMN 802. In the de-registered state, the UE804 is not registered with the CN 806 b of the PLMN 802. The UE contextin CN 806 b holds no valid location or routing information for the UE804, so the UE 804 is not reachable by the CN 806 b of the PLMN 802.However, some parts of the context of the UE may still be stored in theUE 804 and the CN 806 b to avoid performing an authentication procedureduring every registration procedure. In the registered state, the UE 804can be registered with the CN 806 b and the UE 804 can receive theservices that require registration with the CN 806 b.

The UE 804 performs the connection management procedure for establishingand releasing a NAS signaling connection between the UE 804 and the CN806 b of the PLMN 802. The NAS signaling connection enables NASsignaling exchange between the UE 804 and the CN 806 b. In theconnection management, two connection management states (an idle state(CM-IDLE/5GMM-IDLE state) state and a connected state(CM-CONNECTED/5GMM-CONNECTED state)) can be used to reflect the NASsignaling connection of the UE 804 with the CN 806 b. In the idle state,the UE 804 may be in the registered state without having the NASsignaling connection established with the CN 806 b. In the idle state,the UE 804 performs at least one of cell section, cell re-selection,PLMN selection, and so on. In the connected state, the UE 804establishes the NAS signaling with the CN 806 b.

The UE 804 performs a periodic registration procedure with the CN 806 bof the PLMN 802 during the registration state to initially update itsreach ability or the location information with the CN 806 b. The UE 804may perform the periodic registration procedure, according to the 3GPPspecification. In an embodiment, the UE 804 can operate in the MICO modeto perform the periodic registration procedure during the registrationstate. In response to the periodic registration procedure performedduring the registration state, the CN 806 b allocates a periodicregistration timer value for the UE 804 and sends the allocated periodicregistration timer value with a strict indication (“Strictly PeriodicTimer Registration Indication”) to the UE 804. The periodic registrationtimer value may indicate time/duration within which, the UE 804 has toperform the periodic registration procedure again to periodically updateits reach ability or the location to the CN 806 b. In an embodiment, theCN 806 b may allocate the periodic registration timer value to the UE804 based on factors such as, but not limited to, local policies,subscription information, information that has been provided by the UE804, and so on. During the received periodic registration timer value,the UE 804 can enter into the connected state for the data transmissionand into the idle state on completion of the data transmission for anumber of times.

In order to track the periodic registration timer value, the UE 804maintains a periodic tracking area update (PTAU) timer (for example; aT3512 timer). In an embodiment, on receiving the periodic registrationtimer value with the “Strictly Periodic Timer Registration Indication”from the CN 806 b, the UE 804 operates the PTAU timer in a strictlyperiodic registration mode. In the strictly periodic registration mode,the UE 804 applies the received periodic registration timer value to thePTAU timer with the strict indication (“Strictly Periodic TimerRegistration Indication”). Thus, the PTAU timer may behave as a periodicregistration timer with “Strictly Periodic Timer RegistrationIndication”. While operating in the strictly periodic registration mode,the PTAU timer does not terminate/stop, when the UE 804 moves from theidle state/mode to the connected state/mode. While operating in thestrictly periodic registration mode, the PTAU timer does not restart,when the UE 804 moves from the connected mode/state to the idlestate/mode. Thus, in the strictly periodic registration mode, the PTAUtimer starts operating with a value of 0 and expires only when the PTAUtimer reaches the received periodic registration timer value,irrespective of the movement of the UE 804 from the idle state to theconnected state or vice-versa. The UE 804 strictly performs the periodicregistration procedure with the CN 806 b of the PLMN 802 only on theexpiry of the PTAU timer and irrespective of the number of times thatthe UE had been to the connected state or the idle state during thereceived periodic registration timer value.

Further, the UE 804 may initiate the emergency service during thereceived periodic registration timer value or while the PTAU timer isoperating. In an embodiment, the UE 804 switches the behavior of thePTAU timer from the strictly periodic registration mode to a normalperiodic registration mode, on initiating the emergency service. In thenormal periodic registration mode, the UE 804 may apply the periodicregistration timer value to the timer without the strict indication. Inthe normal periodic registration mode, the PTAU timer may terminate,when the UE 804 moves from the idle state to the connected state. In thenormal periodic registration mode, the PTAU timer may reset andrestarted, when the UE 804 moves from the connected state to the idlestate. The UE 804 performs the initiated at least one emergency serviceon the behavior of the timer being switched.

On initiating the emergency service, the UE 804 performs an emergencyattach procedure with the CN 806 b and establishes an emergency PDUsession with the external data network through the CN 806 b (accordingto 3GPP specification). In an embodiment, on establishing the emergencyPDU session, the UE 804 stops operating/disables the PTAU timer andswitches the behavior of the PTAU timer from the periodic registrationtimer value with the “Strictly Periodic Timer Registration Indication”into a normal periodic registration timer/pre-release 16 behavior. In anembodiment, switching the behavior of the PTAU timer on initiating theemergency service includes applying the received periodic registrationtimer value to the PTAU timer without “Strictly Periodic TimerRegistration Indication”.

In an embodiment, if the UE 804 initiates the emergency service whileoperating in the MICO mode, the UE 804 disables the MICO mode, and theCN 806 b disables the registered MICO mode of the UE 804. Further, theUE 804 performs an emergency attach procedure with the CN 806 b andestablishes an emergency PDU session with the external data networkthrough the CN 806 b. Thereafter, the UE 804 stops operating the PTAUtimer and the CN 806 b stops monitoring the PTAU timer of the UE 804.The UE 804 then switches the behavior of the PTAU timer from theperiodic registration timer value with the “Strictly Periodic TimerRegistration Indication” into the normal periodic registrationtimer/pre-release 16 behavior. Thus, when the UE 804 and the CN 806 bdisables the MICO mode on initiating the emergency service, the UE 804and the CN 806 b may behave as if there was no ‘Strictly PeriodicRegistration Timer Indication’ indication has been provided to the UE804 in the last registration procedure.

Once the PTAU timer stops operating and the behavior of the PATU timeris switched, the UE 804 performs the emergency service over theestablished emergency PDU session (according to the 3GPP specification).On completion or release of the emergency service, the UE 804 entersinto the idle state, starts the PTAU timer to operate and remains in theidle state till the expiry of the PTAU timer. In an embodiment, as thebehavior of the PTAU timer is switched, the PTAU timer starts operatingfrom a value of zero and expires once the PTAU timer reaches thereceived periodic registration timer value. Thus, duration of the idlemode may be increased, which further provides a sufficient time/durationfor the UE 804 to receive an emergency call back from the CN 806 b ofthe PLMN 802.

On the expiry of the PATU timer, the UE 804 performs the periodicregistration procedure with the CN 806 b to update the locationinformation and receives the periodic registration timer value. The UE804 may keep track of the periodic registration timer value by applyingthe received periodic registration timer value with the “StrictlyPeriodic Timer Registration Indication” and initiating the timer tooperate. Thus, the UE 804 may continue to operate the PTAU as theperiodic registration timer with the “Strictly Periodic TimerRegistration Indication” till the initiation of the emergency serviceand to switch the behavior of the PTAU timer to the normal periodicregistration timer/pre-release 16 behavior on the initiation of theemergency service. Thus, avoiding possible issues to the emergencyservices.

FIGS. 8A and 8B depict exemplary units/components of the wirelessnetwork 800, but it is to be understood that other embodiments are notlimited thereon. In other embodiments, the wireless network 800 mayinclude less or a greater number of units. Further, the labels or namesof the units are used only for illustrative purpose and does not limitthe scope of the embodiments herein. One or more units can be combinedtogether to perform same or substantially similar function in thewireless network 800.

FIG. 9A depicts the wireless network 800 handling the emergency servicesby switching the behavior of the PTAU timer to the normal periodicregistration timer, wherein the wireless network 800 includes a 5Gsystem (5GS), according to an embodiment of the disclosure. Embodimentsherein are further explained considering the PLMN 802 of the wirelessnetwork 800 including a 5G system (5GS) 806, as an example. As depictedin FIG. 9A, the 5GS 806 includes at least one gNB 806 a, and a 5GC 806b. The 5GC network 806 b may include an AMF 902 configured to supportfunctions such as, but not limited to, termination of NAS signaling, NASciphering and integrity protection, registration management, connectionmanagement, mobility management, access authentication andauthorization, security context management, and so on. The 5GC network806 b also includes an authentication server function (AUSF), a unifieddata management (UDM)/an authentication credential Repository (ARPF), asession management function (SMF), a user plane functionality (UPF), apolicy control function, an application function, a network exposurefunction (NEF), a NF repository function (NRF), a network sliceselection function (NSSF), and so on (not shown).

The UE 804 can be configured to connect to the 5GC network 806 b throughthe gNB 806 a. The UE 804 can also be configured to perform theregistration management procedure with the AMF 902 of the CN 806 b toregister its reach ability/location information, mobility registeredstate, and so on.

As depicted in FIG. 9B, the UE 804 includes a memory 904, acommunication interface 906, a display 908, and a periodic registrationcontroller 910. The UE 804 can also include at least one transceiver,processing circuitry, a storage unit, a input/output (I/O) module, andso on (not shown).

The memory 904 can store at least one of the received periodicregistration value, the PLMN_IDs, and so on. Examples of the memory 904can be, but not limited to, NAND, embedded Multi Media Card (eMMC),Secure Digital (SD) cards, Universal Serial Bus (USB), Serial AdvancedTechnology Attachment (SATA), solid-state drive (SSD), and so on.Further, the memory 904 may include one or more computer-readablestorage media. The memory 904 may include non-volatile storage elements.Examples of such non-volatile storage elements may include magnetic harddiscs, optical discs, floppy discs, flash memories, or forms ofelectrically programmable memories (EPROM) or electrically erasable andprogrammable (EEPROM) memories. In addition, the memory 904 may, in someexamples, be considered a non-transitory storage medium. The term“non-transitory” may indicate that the storage medium is not embodied ina carrier wave or a propagated signal. However, the term“non-transitory” should not be interpreted to mean that the memory 904is non-movable. In certain examples, a non-transitory storage medium maystore data that can, over time, change (e.g., in Random Access Memory(RAM) or cache).

The communication unit 906 can be configured to enable the UE 804 toconnect with at least one of the at least one RAN 806 a of the PLMN 802over an interface. Examples of the interface can be at least one of awired interface, a wireless interface (for example: an air interface, anNu interface, or the like), a wireless fronthaul interface, a wired orwireless backhaul interface, or any structure supporting communicationsover a wired or wireless connection. The display 908 can be configuredto enable the user to interact with the UE 804. The display 908 can alsobe configured to receive a request from the user for initiating theemergency services.

The periodic registration controller 910 can be at least one of a singleprocesser, a plurality of processors, multiple homogeneous orheterogeneous cores, multiple Central Processing Units (CPUs) ofdifferent kinds, microcontrollers, special media, and otheraccelerators. The periodic registration controller 910 can be configuredto perform the registration management procedure and the connectionmanagement procedure with the AMF 902 of the 5GC 806 b.

The periodic registration controller 910 performs the registrationmanagement procedure to register/de-register with the AMF 902 of the CN806 b and to establish the UE context in AMF 902 of the CN 806 b. Theperiodic registration controller 910 maintains a registered state or aregistration attempting state or a registration update needed state(5GMM REGISTERED state or 5GMMREGISTERED.ATTEMPTING-REGISTRATION-UPDATE,or 5GMM-REGISTERED.UPDATE-NEEDED state) and a 5GMM-DEREGISTERED statefor reflecting the registration status of the UE 804. In the5GMM-DEREGISTERED state, the periodic registration controller 910 maynot be registered with the AMF 902 of the CN 806 b. In the5GMM-REGISTERED state, the periodic registration controller 910 mayperform the periodic registration procedure with the AMF 902 of the CN806 b to periodically update the location information/reach ability,mobility registration update, and so on with the AMF 902. The periodicregistration controller 910 performs the connection management procedurefor establishing and releasing the NAS signaling connection between theUE 804 and the AMF 902. The NAS signaling connection enables NASsignaling exchange between the UE 804 and the CN 806 b. In theconnection management, two connection management states a CM-5GMM-IDLEstate and a 5GMM-CONNECTED state can be used to reflect the NASsignaling connection of the UE 804 with the AMF 902. In the CM-5GMM-IDLEstate, the UE 804 may be in the registered state without having the NASsignaling connection established with the AMF 902. In the CM-5GMM-IDLEstate, the periodic registration controller 910 of the UE 804 performsat least one of cell section, cell re-selection, PLMN selection, and soon. In the connected state, the periodic registration controller 910 ofthe UE 804 establishes the NAS signaling with the AMF 902.

The periodic registration controller 910 can be configured to performthe periodic registration procedure with the AMF 902 of the CN 806 b andreceives the periodic registration timer value from the AMF 902. In anembodiment, the periodic registration controller 910 can enable the UE804 to operate in the MICO mode to perform the registration procedure.

The periodic registration controller 910 can be further configured tomaintain the PTAU timer for tracking the received periodic registrationtimer value. The periodic registration controller 910 enables the PTAUtimer to operate/behave as the periodic registration timer with the“Strictly Periodic Registration Timer Indication” by applying thereceived periodic registration timer value and the “Strictly PeriodicRegistration Timer Indication” to the PTAU timer. The PTAU timer maystart from the value of 0 and expires on reaching the received periodicregistration timer value. When the PTAU timer expires, the periodicregistration controller 910 enables the UE 804 to perform the periodicregistration procedure with the AMF 902 by entering into the 5GMMREGISTERED state for updating the location information/mobilityregistration update with the AMF 902. In an embodiment, the periodicregistration controller 910 does not restart the PTAU timer if the UE804 enters into the 5GMM-CONNECTED state for the data transmission orinto the 5GMM-IDLE state on completion of the data transmission.

The periodic registration controller 910 can be further configured toswitch the behavior of the PTAU timer from the periodic registrationtimer with the “Strictly Periodic Registration Timer Indication” intothe normal periodic registration timer value when the UE 804 initiatesthe emergency service on receiving a request from the user for theemergency service. In an embodiment, the UE 804 may initiate theemergency service when the UE 804 is in the 5GMM-CONNECTED state. In anembodiment, the UE 804 may initiate the emergency service when the UE804 is operating in the MICO mode.

When the emergency service is initiated in the 5GMM-CONNECTED state ofthe UE 804, the periodic registration controller 910 enables the UE 804to perform the emergency attach procedure with the AMF 902 forestablishing the emergency PDU session. During the emergency attachprocedure, the periodic registration controller 910 of the UE 804 sendsan emergency registration request to the AMF 902 through the associatedRAN/gNB 806 a by enabling the UE 804 to enter into an emergencyregistered state. On receiving the emergency registration request fromthe periodic registration controller 910 of the UE 804, the AMF 902establishes the emergency PDU session between the UE 804 and theexternal data network without authenticating the UE 804. Once theemergency PDU session has been established for the UE 804, the periodicregistration controller 910 stops operating the PTAU timer. The periodicregistration controller 910 then applies the received periodicregistration timer value without the “Strictly Periodic RegistrationTimer Indication” to the PTAU timer. Thus, the PTAU timer may switch itsbehavior from the periodic registration timer with the “StrictlyPeriodic Registration Timer Indication” into the normal periodicregistration timer value.

When the emergency service is initiated in the MICO mode of the UE 804,the periodic registration controller 910 enables the UE 804 to disablethe MICO mode. The periodic registration controller 910 also sends adisable request to the AMF 902 for disabling the registered MICO modefor the UE 804. On disabling the MICO mode, the periodic registrationcontroller 910 performs the emergency attach procedure with the AMF 902for establishing the emergency PDU session between the UE 804 and theexternal data network. Once the emergency PDU session has beenestablished for the UE 804, the periodic registration controller 910stops operating the PTAU timer, and the AMF 902 stops monitoring theperiodic registration timer value allocated for the UE 804. Further, theperiodic registration controller 910 of the UE 804 and the AMF 902behaves as if no “Strictly Periodic Registration Timer Indication” wasgiven to the UE 804 in the last registration attempt. The periodicregistration controller 910 then switches the behavior of the PTAU timerby applying only the received periodic registration timer value (i.e.without the “Strictly Periodic Registration Timer Indication”) to thePTAU timer. Thus, the PTAU timer may act as the normal periodicregistration timer/pre-release 16 behavior.

On switching the behavior of the PTAU timer to the normal periodicregistration timer, the periodic registration controller 910 enables theUE 804 to perform the emergency services over the established emergencyPDU session. Once the emergency service is completed, the periodicregistration controller 910 enables the UE 804 to enter into the5GMM-IDLE state and starts the PTAU timer. The periodic registrationcontroller 910 allows the UE 804 to remain in the 5GMM-IDLE state tillthe expiry of the PTAU timer. When the PTAU timer expires, the periodicregistration controller 910 enables the UE 804 to detach locally fromthe AMF 902 of the CN 806 b (according to 3GPP TS 24.501 subclause5.3.7) due to its emergency registered state. The periodic registrationcontroller 910 then performs the periodic registration procedure withthe AMF 902 by entering into the 5GMM-REGISTERED state.

FIG. 10 is an example sequence diagram depicting the handling of theemergency service by enabling the PTAU timer supporting the “StrictlyPeriodic Registration Timer Indication” to act as the normal periodicregistration timer, according to an embodiment of the disclosure.

At step 1001, the UE 804 performs the periodic registration procedurewith the CN 806 b of the PLMN 802 during the registered state andreceives the periodic registration timer value from the CN 806 b. In anexample herein, consider that the UE 804 may operate in the MICO mode,and the periodic registration timer value may be 12 minutes (mins). Atstep 1002, the UE 804 initiates the PTAU timer by applying the receivedperiodic registration timer value with the “Strictly PeriodicRegistration Timer Indication”. At step 1003, the UE 804 then entersinto the connected state. After 4 mins of entering into the connectedstate, at step 1004, the UE 804 enters into the idle mode. After 2 minsof entering into the idle state, at step 1005, the UE 804 starts thedata transmission to the CN 806 b by entering into the connected stateand enters into the idle state on completion of the data transmission.In an embodiment, the UE 804 does not re-start the PTAU timer, as thePTAU timer behaves as the periodic registration timer with the “StrictlyPeriodic Registration Timer Indication”.

After 3 mins of entering into the idle mode, at step 1006, the UE 804may receive a request from the user to initiate an emergency call. TheUE 804 initiates the emergency call by disabling the MICO mode. The UE804 further performs the emergency attach procedure with the CN 806 b byentering into the emergency registered state to establish the emergencyPDU session with the external data network. Once the emergency PDUsession is established, the UE 804 stops the PTAU timer, and the CN 806b stops monitoring the periodic registration timer value sent to the UE804. The UE 804 further switches the behavior of the PTAU timer from theperiodic registration timer with the “Strictly Periodic RegistrationTimer Indication” to the periodic registration timer value.

On switching the behavior of the PTAU timer, the UE 804 performs theemergency call over the established PDU session. Once the emergency callis completed, at step 1007, the UE 804 enters into the idle mode. Whenthe UE 804 enters into the idle state, the UE 804 starts the PTAU timer.As the behavior of the PTAU timer is switched, the PTAU timer startsfrom a value of 0 and expires on the timer reaching 12 mins. The UE 804further remains in the idle state till the expiry of the PTAU timer,which provides a sufficient time (for example: 12 mins) for the UE 804to receive the emergency call back from the CN 806 b.

When the PTAU timer expires, at step 1008, the UE 804 locally detachesfrom the CN 806 b, since the UE 804 has attached with the CN 806 b forperforming the emergency attach procedure. The UE 804 further performsthe periodic registration procedure with the CN 806 b by entering intothe registration state.

FIG. 11 is a flow diagram 1100 depicting a method for handling theemergency services by switching the behavior of the timer, according toan embodiment of the disclosure.

At step 1102, the method includes receiving, by the UE 804, the periodicregistration timer value with the “Strictly Periodic Registration TimerIndication” indication from the CN 806 b.

At step 1104, the method includes operating, by the UE 804, the timer inthe strictly periodic registration mode in response to the receivedperiodic registration timer value with the “Strictly PeriodicRegistration Timer Indication” indication.

At step 1106, the method includes initiating, by the UE 804, the atleast one emergency service while the timer is operating. At step 1108,the method includes switching, by the UE 804, the behavior of the timerfrom the strictly periodic registration mode to a normal periodicregistration mode on initiating the at least one emergency service.

At step 1110, the method includes performing, by the UE 804, theinitiated at least one emergency service on the behavior of the timerbeing switched. The various actions in method 1100 may be performed inthe order presented, in a different order or simultaneously. Further, insome embodiments, some actions listed in FIG. 11 may be omitted.

Embodiments herein further enable the UE 804 connected to at least oneof the CN 806 b of the PLMN 802 to handle priority services. Examples ofthe priority services can be, but not limited to, Mission CriticalServices (MCS), Vehicle-to-everything (V2X) communication, MobilePositioning System (MPS) network related services, Ultra-reliablelow-latency communication (URLLC) services, and so on.

FIGS. 12A, 12B, and 12C are flow diagrams depicting the handling of theat least one priority service, according to an embodiment of thedisclosure. The UE 804 executes 1201 a-1203 a, 1201 b-1203 b, 1201c-1203 c, when the UE receives data or signaling related to at least oneof the Mission Critical Service, the V2X communication, the MPS networkrelated services, the URLLC services, and so on.

As depicted in FIG. 12A, at step 1201 a, the UE 804 may be in aregistration attempting state (for example:5GMM.DEREGISTERED.ATTEMPTING-REGISTRATION) state and the UE 804executes/operates a timer (for example; at least one of a T3510 timer, aT3511 timer, a T3502 timer, or the like). At step 1202 a, the UE 804receives a request from an upper layer for the at least one priorityservice to establish signaling (for example: MCS signaling, V2signaling, URLCC signaling, or the like) or user data. In such a case,at step 1203 a, the UE 804 stops operating the timer and sends aregistration request with an initial registration to the CN 806 b.

As depicted in FIG. 12B, at step 1201 b, the UE 804 may be in aregistration attempting update state (for example:5GMMREGISTERED.ATTEMPTING-REGISTRATION UPDATE state and the UE 804operates the timer (for example; at least one of the T3510 timer, theT3511 timer, the T3502 timer, or the like). At step 1202 b, the UE 804the UE 804 receives a request from an upper layer for the at least onepriority service to establish signaling or user data. In such a case, atstep 1203 b, the UE 804 stops operating the timer and sends theregistration request with the initial registration to the CN 806 b.

As depicted in FIG. 12C, at step 1201 c, the UE 804 is in a registerwith an idle state (for example: 5GMMREGISTERED with 5GMM IDLE state)and the UE 804 executes/operates a T3525 timer. At step 1202 c, the UE804 receives a request from an upper layer for the at least one priorityservice to establish signaling or user data. In such a case, at step1203 c, the UE 804 transmits a service request message related to the atleast one priority service to the CN 806 b.

In an embodiment, the UE 804 may operate a back off timer, T3346. Insuch a case, if the UE receives a request from the normal services, theUE 804 does not transmit a NAS signaling message (for example: aregistration message, a service message, or the like) related to thenormal service to the CN 806 b. In an embodiment, the UE 804 continuesoperating the back off timer and does not send the NAS signaling messageto the CN 806 b. In an embodiment, the UE 804 stops operating the backoff timer and the NAS signaling to resume the allowed normal service.

In an embodiment, if the UE 804 receives the request for the at leastone priority service to establish the signaling or the user while theback off timer is operating, the UE 804 transmits a NAS message (forexample, a registration request or service request message) related tothe at least one priority service to the CN 806 b.

The embodiments disclosed herein can be implemented through at least onesoftware program running on at least one hardware device and performingnetwork management functions to control the elements. The elements shownin FIGS. 2A-12C can be at least one of a hardware device, or acombination of hardware device and software module.

FIG. 13 schematically illustrates the base station according to anembodiment of the disclosure.

Referring to the FIG. 13, the Base station 1300 may include a processor1310, a transceiver 1320 and a memory 1330. However, all of theillustrated components are not essential. The Base station 1300 may beimplemented by more or less components than those illustrated in FIG.13. In addition, the processor 1310 and the transceiver 1320 and thememory 1330 may be implemented as a single chip according to anotherembodiment.

The aforementioned components will now be described in detail.

The processor 1310 may include one or more processors or otherprocessing devices that control the proposed function, process, and/ormethod. Operation of the Base station 1300 may be implemented by theprocessor 1310.

The transceiver 1320 may include a RF transmitter for up-converting andamplifying a transmitted signal, and a RF receiver for down-converting afrequency of a received signal. However, according to anotherembodiment, the transceiver 1320 may be implemented by more or lesscomponents than those illustrated in components.

The transceiver 1320 may be connected to the processor 1310 and transmitand/or receive a signal. The signal may include control information anddata. In addition, the transceiver 1320 may receive the signal through awireless channel and output the signal to the processor 1310. Thetransceiver 1320 may transmit a signal output from the processor 1310through the wireless channel.

The memory 1330 may store the control information or the data includedin a signal obtained by the Base station 1300. The memory 1330 may beconnected to the processor 1310 and store at least one instruction or aprotocol or a parameter for the proposed function, process, and/ormethod. The memory 1330 may include read-only memory (ROM) and/or randomaccess memory (RAM) and/or hard disk and/or CD-ROM and/or DVD and/orother storage devices.

In an embodiment, the transceiver 1320 may transmit, to a User Equipment(UE), at least one signal for selecting a plurality of non-CAG cellsavailable in a location of the UE, connect to the UE based on the atleast one signal and provide at least one emergency service to the UE.

FIG. 14 schematically illustrates a user equipment (UE) according to anembodiment of the disclosure.

Referring to the FIG. 14, the UE 1400 may include a processor 1410, atransceiver 1420 and a memory 1430. However, all of the illustratedcomponents are not essential. The UE 1400 may be implemented by more orless components than those illustrated in FIG. 14. In addition, theprocessor 1410 and the transceiver 1420 and the memory 1430 may beimplemented as a single chip according to another embodiment.

The aforementioned components will now be described in detail.

The processor 1410 may include one or more processors or otherprocessing devices that control the proposed function, process, and/ormethod. Operation of the UE 1400 may be implemented by the processor1410.

The transceiver 1420 may include a RF transmitter for up-converting andamplifying a transmitted signal, and a RF receiver for down-converting afrequency of a received signal. However, according to anotherembodiment, the transceiver 1420 may be implemented by more or lesscomponents than those illustrated in components.

The transceiver 1420 may be connected to the processor 1410 and transmitand/or receive a signal. The signal may include control information anddata. In addition, the transceiver 1420 may receive the signal through awireless channel and output the signal to the processor 1410. Thetransceiver 1420 may transmit a signal output from the processor 1410through the wireless channel.

The memory 1430 may store the control information or the data includedin a signal obtained by the UE 1400. The memory 1430 may be connected tothe processor 1410 and store at least one instruction or a protocol or aparameter for the proposed function, process, and/or method. The memory1430 may include read-only memory (ROM) and/or random access memory(RAM) and/or hard disk and/or CD-ROM and/or DVD and/or other storagedevices.

The embodiments disclosed herein describe methods and systems forhandling emergency services in a wireless network. Therefore, it isunderstood that the scope of the protection is extended to such aprogram and in addition to a computer readable means having a messagetherein, such computer readable storage means contain program code meansfor implementation of one or more steps of the method, when the programruns on a server or mobile device or any suitable programmable device.The method is implemented in a preferred embodiment through or togetherwith a software program written in e.g. Very high speed integratedcircuit Hardware Description Language (VHDL) another programminglanguage, or implemented by one or more VHDL or several software modulesbeing executed on at least one hardware device. The hardware device canbe any kind of portable device that can be programmed. The device mayalso include means which could be e.g. hardware means like e.g. an ASIC,or a combination of hardware and software means, e.g. an ASIC and anFPGA, or at least one microprocessor and at least one memory withsoftware modules located therein. The method embodiments describedherein could be implemented partly in hardware and partly in software.Alternatively, the invention may be implemented on different hardwaredevices, e.g. using a plurality of CPUs.

Although the present disclosure has been described with variousembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A method performed by a user equipment (UE) forhandling emergency services in a wireless network, the methodcomprising: initiating at least one emergency service while operating ina closed access group (CAG) only mode; selecting a non-CAG cell from aplurality of non-CAG cells in a public land mobile network (PLMN); andperforming the initiated at least one emergency service by camping ontothe selected non-CAG cell.
 2. The method of claim 1, wherein thewireless network includes at least one non-public network (NPN)connected to the PLMN, wherein the at least one NPN is at least one CAGcell.
 3. The method of claim 1, wherein in the CAG only mode, the UEconnects only to at least one CAG cell to access the PLMN, wherein theat least one CAG cell provides at least one private service to the UE.4. The method of claim 1, wherein each of the plurality of non-CAG cellsis a public radio access network (RAN) connected to at least one corenetwork (CN) of at least one radio access technology (RAT) present inthe PLMN.
 5. The method of claim 4, wherein each non-CAG cell supportsat least one CAG cell and provides at least one normal communicationservice and the at least one emergency service to the UE.
 6. The methodof claim 1, wherein selecting the non-CAG cell includes: disabling theCAG only mode; determining the plurality of non-CAG cells available in alocation of the UE based on at least one signal broadcasted by theplurality of non-CAG cells; and selecting the non-CAG cell from theplurality of non-CAG cells based on at least one factor associated withthe at least one signal broadcasted by the plurality of non-CAG cells,wherein the at least one factor includes at least one of signalstrength, and reference signal receive power.
 7. The method of claim 6,wherein the UE selects the non-CAG cell for the initiated at least oneemergency service when the UE does not determine at least one CAG cellin the location, or when the at least one CAG cell connected to the UEdoes not support the initiated at least one emergency service.
 8. Themethod of claim 1, wherein performing the initiated at least oneemergency service includes: camping on to the selected non-CAG cell andestablishing a radio resource control (RRC) connection with the selectednon-CAG cell, wherein the non-CAG cell connects the UE to an associatedat least one core network (CN); establishing an emergency protocol dataunit (PDU) session with an external data network through the at leastone CN by performing an emergency attach procedure with the at least oneCN through the selected non-CAG cell; and performing the initiated atleast one emergency service over the established emergency PDU session.9. The method of claim 8, further comprises: entering, by the UE, intoan idle mode on completing the at least one initiated emergency service;remaining, by the UE, in the idle mode for a pre-defined period of time;and enabling, by the UE, the CAG only mode on an expiry of thepre-defined period of time.
 10. The method of claim 9, wherein the UEenables the CAG only mode by performing a registration update procedurewith the at least one CN of the PLMN.
 11. The method of claim 1, furthercomprising: establishing, by the UE, the emergency PDU session with atleast one CAG cell for performing the initiated at least one emergencyservice, when the UE is camped on the at least one CAG cell during theCAG only mode; determining, by the UE, a connection loss with the campedat least one CAG cell, while performing the at least one emergencyservice through the camped at least one CAG cell; and selecting, by theUE, the non-CAG cell for completing the at least one emergency serviceon determining the connection loss with the camped at least one CAGcell.
 12. The method of claim 1, the method further comprising:receiving, by the UE, a periodic registration timer value with astrictly periodic registration timer indication from a core network(CN); operating, by the UE, a timer in a strictly periodic registrationmode in response to the received periodic registration timer value withthe strictly periodic registration timer indication; initiating, by theUE, at least one emergency service while the timer is operating;switching, by the UE, behavior of the timer from the strictly periodicregistration mode to a normal periodic registration mode on initiatingthe at least one emergency service; and performing, by the UE, theinitiated at least one emergency service on the behavior of the timerbeing switched.
 13. A user equipment (UE) in a wireless network, the UEcomprising: a memory; and a controller coupled to the memory configuredto: initiate at least one emergency service while the UE is operating ina closed access group (CAG) only mode; select a non-CAG cell from aplurality of non-CAG cells in a public land mobile network (PLMN); andperform the initiated at least one emergency service by enabling the UEto camp onto the selected non-CAG cell.
 14. The UE of claim 13, whereinthe wireless network includes at least one non-public network (NPN)connected to the PLMN, wherein the at least one NPN is at least one CAGcell.
 15. The UE of claim 13, wherein in the CAG only mode, the UEconnects only to at least one CAG cell to access the PLMN, wherein theat least one CAG cell provides at least one private service to the UE.16. The UE of claim 13, wherein each of the plurality of non-CAG cellsis a public radio access network (RAN) connected to at least one corenetwork (CN) of at least one radio access technology (RAT) present inthe PLMN.
 17. The UE of claim 13, wherein the controller is furtherconfigured to: disable the CAG only mode; determine the plurality ofnon-CAG cells available in a location of the UE based on at least onesignal broadcasted by the plurality of non-CAG cells; and select thenon-CAG cell from the plurality of non-CAG cells based on at least onefactor associated with the at least one signal broadcasted by theplurality of non-CAG cells, wherein the at least one factor includes atleast one of signal strength, and reference signal receive power. 18.The UE of claim 13, wherein the controller is further configured to:enable the UE to camp on to the selected non-CAG cell and to establish aradio resource control (RRC) connection with the selected non-CAG cell,wherein the non-CAG cell connects the UE to the associated at least oneCN; enable the UE to establish an emergency protocol data unit (PDU)session with an external data network through at least one core network(CN) by performing an emergency attach procedure with the at least oneCN through the selected non-CAG cell; and perform the initiated at leastone emergency service over the established emergency PDU session. 19.The UE of claim 13, wherein the controller is further configured to:enable the UE to establish the emergency PDU session with at least oneCAG cell for performing the initiated at least one emergency service,when the UE is camped on the at least one CAG cell during the CAG onlymode; determine a connection loss with the camped at least one CAG cell,while performing the at least one emergency service through the campedat least one CAG cell; and select the non-CAG cell for completing the atleast one emergency service on determining the connection loss with thecamped at least one CAG cell.
 20. A method performed by a base stationfor handling emergency services in a wireless network, the methodcomprising: transmitting, to a user equipment (UE), at least one signalfor selecting a plurality of non-CAG cells available in a location ofthe UE; connecting to the UE based on the at least one signal; andproviding at least one emergency service to the UE.